1. Field of the Invention
The present invention pertains to conveyor sorting systems, and more particularly, it pertains to reject mechanisms for selectively rejecting articles such as fruit from a conveyor.
2. Description of the Prior Art
In various commercial enterprises relatively fragile articles of different types are conveyed through sorting systems wherein selectively actuated mechanisms are utilized to divert the articles into separate sorting or conveying lanes in accordance with certain qualities or characteristics of the articles. For example, the fresh fruit and vegetable packing industry is one such enterprise wherein easily bruised or otherwise damageable fruit must be sorted and diverted into different processing lanes in accordance with certain inherent characteristics of the fruit (e.g., color, size, etc.). Heretofore, it has been the practice in this industry to use the conventional and time honored methods and means for diverting the fruit from their carrying conveyors despite the rather obvious inadequacies of such methods in certain situations.
For example, probably the most widely used method of diverting singulated articles when such articles are moving in a generally horizontal path on a conveyor involves the use of a pivotable arm which can be selectively actuated to swing from a position out of the path of the articles into an obstructing position over the conveyor to thereby intercept the selected article and deflect it laterally from the conveyor. While this "baseball bat" approach to diverting articles from a conveyor has its obvious advantages in simplicity and reliability, it leaves much to be desired when the articles are fragile and easily damaged (e.g., when the articles are fruit or vegetables) and/or when the articles are moving at a relatively high rate of speed. Prior art patents which teach this primitive method of selective article diversion include the U.S. Pat. Nos. to Driesch et al 3,198,308; Dodge 2,455,741; and Lowe 2,451,104.
An improved article diverting means for fragile articles is provided by air jets which can be selectively operated to direct blasts of air laterally against the moving articles so as to divert them off of their conveying means--such apparatus being shown, for example, in the prior U.S. Pat. Nos. to Bartlett 2,881,919 or Simmons 3,327,850. The problem with the air blast type of diverter, in addition to its relatively high cost, is that where the articles are heavy and occupy a stable position upon the conveying means a rather forceful jet of air is needed in order to accomplish the deflection. This can create difficulties if the article has "soft spots" which are susceptible to concentrated forces. For example, apples (which is a fruit that is typically mechanically sorted during grading or pregrading operations) may have soft spots occasioned by bruises or microbial infection which if subjected to a concentrated air blast would not only result in the destruction of the apple but also in the creation of a disagreeable mess on and about the conveying machinery so as to necessitate a costly stopping of such machinery for the institution of clean-up procedures.
A recently devised mechanism for diverting fruit or the like from a horizontally arranged conveyor is disclosed in the U.S. Pat. No. to Greenwood et al 3,770,111, which issued on Nov. 6, 1973. This mechanism utilizes the aforediscussed air blast devices but, in addition, includes a pair of vertically upwardly movable plungers which are selectively activated to engage the lowermost surface of a fruit as it passes thereover to deflect it laterally of its supporting conveyor surface. While the mechanism disclosed in the Greenwood et al patent constitutes an improvement over the aforedescribed more conventional prior art mechanisms, such device still operates under the same general concept as that of the prior art mechanisms, i.e., the concept of moving a rigid member in a direction so as to intercept a moving article to thereby institute a collision which deflects the article from its original course. Thus, such mechanism is ultimately plagued with the attendant control and fruit damage problems of the other prior art diverter mechanisms.